Customizing ToolTips or mimicking their functionality...

Hi all,
I was wondering how tool tips worked. I basically need to get an image into a tooltip (if possible, which I doubt) or make something that functions similarly to a tooltip. I've tried to just draw directly on the form, but it puts the image on the background behind all the controls, and it can't exceed the bounds of the form. How can i achieve this? Also, i want the picture to be changeable while the "tooltip" is still being displayed. Is that possible?

The event takes place on a textbox, and the tooltip should appear right next to the cursor and should not be limited to the bounds of the form (ie able to draw beyond the sides of the form). All I would need in my tooltip would be a picture and perhaps a small string caption. Any help would be great.

I'm sorry, I just realized I didn't specify the language. I'm working on a C# windows application, and I only used the JavaScript to show an example of the functionality I'm looking for from the user perspective. I just have the additional twist of being able to update the image without having to mouse off and then back on. Rather, you should be able to watch the image change as you're mouse is over the textbox if it gets updated.

Well, it is a possibility, but I was hoping for something that didn't use other forms, because then you split the event handling into two seperate forms rather than keep it all in one place. Is it possible?